Method and apparatus for a chopped two-chip cinematography camera

ABSTRACT

A method of capturing a color image includes steps of operating a first sensor of a camera to integrate a first charge over a first time interval, operating a second sensor of the camera to integrate a second charge over a second time interval and scanning the first and second sensors to readout the respective first and second charges during a third time interval. The first time interval overlaps the second time interval. The third time interval includes no overlapping time with the first time interval. The third time interval includes no overlapping time with the second time interval.

BACKGROUND OF THE INVENTION

The priority benefit of the Jan. 24, 2001 filing date of provisionalapplication Ser. No. 60/263,528, the Jan. 25, 2001 filing date ofprovisional application Ser. No. 60/263,707, and the Apr. 19, 2001filing date of provisional application Ser. No. 60/284,697 are herebyclaimed.

FIELD OF THE INVENTION

The present invention relates to a color cinematography camera withsolid state imaging sensors. In particular, the invention relates to ascanning wheel-type color camera using plural sensors.

DESCRIPTION OF RELATED ART

Color cameras are known. One type of color camera uses a single CCDimaging sensor with a Bayer pattern overlaying color filter. A Bayerpattern overlaying filter uses four sensor elements per pixel. Theoverlaying color filter, transmits green light into the first and secondsensor elements, transmits blue into the third sensor element andtransmits red light into the fourth sensor element. The four elementsmake up one pixel of a digital color camera. This tends to limit theresolution achievable by such color cameras.

Another type of color camera uses expensive prisms and custom lenses andthree CCD imaging sensors. Ordinary spherical objective lenses pass theimage light into a prism as converging (not parallel) rays of light.Because of dispersion characteristics that any optical material impartson light passing through the material, the converging (not parallel)rays of light undergo different dispersions since the different rays oflight have different path lengths. This leads to noticeable colordistortions. To over come this, known cameras use a more complex colorcorrected objective lens.

In FIG. 29, known camera 2000 includes lens 2010 to focus an imageconjugate through color filter wheel 2050 onto imaging sensor 2040.Color filter wheel 2050 is divided into three color sectors, each sectorrepresenting one-third of a circle. Each sector 2052, 2054 and 2056passes light (i.e., transmits, not reflects) of a different one of thethree primary colors (i.e., blue, red and green). A color wheel assemblyincludes motor 2020 to spin color filter wheel 2050. To obtain a fullcolor image requires that sensor 2040 form three complete images foreach revolution of color filter wheel 2050. When the camera systemrequires that moving images be captured at a particular rate, the timeavailable for capture of each color image is just one-third of the frametime. This limits the sensitivity of the camera.

It should be noted that rotatable color wheels have been used in theprojection TV industry (not cameras). For example, see U.S. Pat. Nos.5,868,482 and 6,024,453.

Interline transfer (ILT) CCD sensors include an electronic shutterfunction to prevent smear effects. Known cameras require the ILT designto control smear.

It is desired to control smear and provide near synchronous imaging witha 2-chip frame transfer CCD or full-frame CCD based motion picturecamera that will operate within the optical constraints of existing 35mm motion picture lenses (the focal flange distance restricts theoptions for placement of the components).

Advantages of this approach include that the camera does not require anILT sensor architecture, has higher fill factor, simpler clocking, largedie size achieved through stitching not currently believed to beavailable to ILT designs, and does not require micro-lenses for recoveryof fill factor and hence improved MTF (modulation transfer finction).

SUMMARY OF THE INVENTION

An advantage of the present invention is that color artifacts areminimized. Another advantage is that the color quality of the image isimproved.

These and other advantages are achieved in an a camera that includes afirst sensor disposed to image light that propagates along a reflectedaxis and a second sensor disposed to image light that propagates along adirect axis. The camera further includes a rotatable structure disposedto defme a rotation plane that is oblique to both the reflected axis andthe direct axis. The rotatable structure has a first reflection sector,a first opaque sector disposed adjacent to the first reflection section,a first transmission sector disposed adjacent to the first opaquesector, a second reflection sector disposed adjacent to the firsttransmission sector, and a second transmission sector disposed adjacentto the second reflection sector.

These and other advantages are also achieved with a method of capturinga color image includes steps of operating a first sensor of a camera tointegrate a first charge over a first time interval, operating a secondsensor of the camera to integrate a second charge over a second timeinterval and scanning the first and second sensors to readout therespective first and second charges during a third time interval. Thefirst time interval overlaps the second time interval. The third timeinterval includes no overlapping time with the first time interval. Thethird time interval includes no overlapping time with the second timeinterval.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in detail in the following descriptionof preferred embodiments with reference to the following figureswherein:

FIG. 1 is a schematic diagram of a preferred embodiment of a cameraaccording to the present invention;

FIG. 2 is a schematic diagram of a first embodiment of a rotatablestructure;

FIG. 3 is a schematic diagram of a second embodiment of the rotatablestructure;

FIG. 4 is a schematic diagram of a third embodiment of the rotatablestructure;

FIG. 5 is a schematic diagram of fourth embodiment of the rotatablestructure;

FIG. 6 is a schematic diagram of a fifth embodiment of the rotatablestructure;

FIG. 7 is a schematic diagram of a choppered-wheel embodiment of therotatable structure;

FIG. 8 is a illustration of a imaging sensor pixel array;

FIG. 9 is an illustration of pixels overlaid with color microfilters;

FIG. 10 is an illustration of an opaque reflection sector coated with acolor selective coating;

FIG. 11 is an illustration of a transparent reflection sector coatedwith a color selective coating;

FIG. 12 is an illustration of a transmission sector coated with a colorselective coating;

FIG. 13 is a schematic diagram of a sixth embodiment of the rotatablestructure having a larger reflection sector;

FIG. 14 is a schematic diagram of a seventh embodiment of the rotatablestructure having a larger transmission sector;

FIG. 15 is a schematic diagram of an eighth embodiment of the rotatablestructure having a larger reflection sector;

FIG. 16 is a schematic diagram of a ninth embodiment of the rotatablestructure having a larger transmission sector;

FIG. 17 is a schematic diagram of a preferred embodiment of a 3-chipcamera according to the present invention;

FIG. 18A is a schematic diagram of a rotatable structure to be used inthe 3-chip camera of the present invention;

FIG. 18B is a front view of the rotatable structures of the 3-chipcamera in operation;

FIGS. 18C and 18D are plan and sectional views of an alternativeembodiment of the rotatable structure of the present invention;

FIG. 19 is an graphic illustration of obtaining a third color from twoselected colors using post-processing FIG. 20 is a timing diagram of theoperation of the first embodiment of the rotatable structure;

FIG. 21 is a timing diagram of the operation of the second embodiment ofthe rotatable structure;

FIG. 22 is a timing diagram of an alternative operation of the secondembodiment of the rotatable structure;

FIG. 23 is a timing diagram of the operation of the third embodiment ofthe rotatable structure;

FIG. 24 is a timing diagram of the operation of the fourth embodiment ofthe rotatable structure;

FIG. 25 is a timing diagram of the operation of the fifth embodiment ofthe rotatable structure;

FIG. 26 is a timing diagram of the operation of the choppered-wheel;

FIG. 27 is a timing diagram of the operation of the 3-chip camera;

FIG. 28 is a schematic diagram of an alternative embodiment of theinvention; and

FIG. 29 is a schematic diagram of a known color camera.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1, camera 10 includes lens 12, first imaging sensor 14, secondimaging sensor 16, and rotatable structure 100. First imaging sensor 14is disposed to receive light that propagates along reflected axis 28 andsecond imaging sensor 16 is disposed to receive light that propagatesalong direct axis 26. Rotatable structure 100 is disposed to define arotation plane that is oblique to both reflected axis 28 and direct axis26. In operation, motor 24 rotates axle 22 that in turn rotatesrotatable structure 100. Lens 12 focuses an image conjugate onto secondimaging sensor 16 along direct axis 26 such that second imaging sensor16 converts the image light into electrical signals. Lens 12 alsofocuses the image conjugate onto first imaging sensor 14 along reflectedaxis 28. The image light through lens 12 along direct axis 26 isreflected from a reflection sector of rotatable structure 100 topropagate along reflected axis 28. First imaging sensor 14 converts theimage light into electrical signals. Rotatable structure 100 is formedas a ring having an inner radius such that the image light focused bylens 12 does not impinge on motor 24 but only on the surface ofrotatable structure 100. Other formations of rotatable structure 100 arealso possible that satisfy the need to avoid motor 24.

In some variants of the invention, camera 10 also includes first colorfilter 18 disposed along reflected axis 28 between rotatable structure100 and first sensor 14. In other variants of the invention, camera 10further includes second color filter 20 disposed along direct axis 26between rotatable structure 100 and second sensor 16.

In one embodiment, the rotatable structure is first structure 110 (FIG.2) that includes first transmission sector 112, first reflection sector114 disposed adjacent to first transmission sector 112, secondtransmission sector 116 disposed adjacent to first reflection sector114, and second reflection sector 118 disposed adjacent to secondtransmission sector 116. First and second transmission sectors 112 and116 may be gaps (e.g., air-filled) or, in an alternative embodiment, asolid transparent media (e.g., glass or polycarbonate), as indicated inFIG. 2 by the dashed perimeter line. In some embodiments, each sectorsubtends one-fourth of a circle. Other embodiments may vary as describedfurther herein.

In another embodiment, the rotatable structure is second structure 120(FIG. 3) that includes first reflection sector 122, first opaque sector124 disposed adjacent to first reflection sector 122, and firsttransmission 126 sector disposed adjacent to first opaque sector 124.First opaque sector 124 is formed of an absorbing material (e.g., smokedglass, etc.) such that first opaque sector 124 neither reflects nortransmits light. Imaging sensors 14 and 16 are operated with a timingcontrol such that when first opaque sector 124 is positioned at the exitpupil of lens 12, the charge transfer operation of both imaging sensors12 and 16 is performed. The length of the arc, or angular extent, offirst opaque sector 124 is designed such that imaging sensors 14 and 16remain in darkness for a time at least as long as is required to affectthe transfer of image to the storage areas. Since second structure 120rotates uniformly at a frame rate, first opaque sector 124 is designedto be large enough to provide blanking over the range of frame ratesanticipated for camera 10.

The use of first opaque sector 124 with second structure 120 as anopaque shutter has particular advantages. With an opaque shutteredarrangement, imaging sensors 14 and 16 can be of a type referred to as afull-frame, or full-field, sensor. A full-frame sensor includes pluralvertical channels over top of which are disposed plural horizontal polyclock lines and at a terminal end of the channels is a horizontalreadout register. For example, a full-frame sensor to provide 512 linesby 683 pixels per line requires 683 vertical channels and 3 times 512horizontal poly clock lines (for a three phase clocking structure). Thissimple sensor architecture has no electronic shutter capability.Instead, it relies on first opaque sector 124 to provide a shutterfunction. The full-frame sensors are controlled to collect the image(integrate) over the full time that the image light impinges on firsttransmission sector 126 and first reflection sector 122. Then, thefull-frame sensors are controlled to shift the collected image down thevertical shift registers defined by the vertical channels and overlyingclock lines into and out of the horizontal shift register over the timethat the image light impinges on first opaque sector 124. The full-framesensors use first opaque sector 124 to freeze the image so it will notsmear while the image is being shifted out of the sensors. Thefull-frame sensor provides a maximum fill factor since it uses none ofits topography under a light shield to provide an electronic shutter.

Actually, second imaging sensor 16 (in the direct path) is shutteredwhen either first opaque sector 124 or first reflection sector 122blocks light along the direct path. Second imaging sensor 16 may use thetime when either or both sectors block light as a time for smear-freereadout. First imaging sensor 14 (in the reflection path) may similarlyuse either or both of first opaque sector 124 or first transmissionsector 126 for smear-free readout.

First transmission sector 126 may be a gap (air-filled) or, in analternative embodiment, a solid transparent media (e.g., glass orpolycarbonate), as indicated in FIG. 3 by the dashed perimeter line.Second structure 120 may also include counterweights 126 and 128, whichserve to offset the mass distribution differential caused bytransmission sector 126 when transmission sector 126 is an air-filledgap, thus preserving dynamic balance in second structure 120. Thedynamic balancing function of second structure 120 may be achieved byother means, for example, relocating the placement of axle attachmentpoint 22 to create a dynamically balanced rotatable structure. In someembodiments, each sector subtends one-third of a circle. Otherembodiments may vary as described further herein.

Camera with Electronic Shutter

Camera 10 produces a complete color image by obtaining the imageconjugate in a minimum of three colors, e.g., red, blue, and green. Therequisite colors may be obtained using a variety of methods, as will bedescribed herein. With reference to first structure 110 (FIG. 2), inoperation, the light that propagates along reflected axis 28 isreflected from at least one of reflection sectors 114 and 118 and thelight that propagates along direct axis 26 passes through at least oneof transmission sectors 112 and 116. In one embodiment, reflectionsectors 114 and 118 are mirrored surfaces such that the light thatimpinges onto first imaging sensor 14 includes the entire spectrum ofvisible light. Similarly, the light that passes through transmissionsectors 112 and 116 and impinges onto second imaging sensor 16 alsoincludes the entire spectrum of visible light.

In this embodiment, either first imaging sensor 14 or second imagingsensor 16 includes an array 210 of pixel groups 220, as seen in FIG. 8.First pixel group 220 includes a plurality of pixels, e.g., pixels 222,224, 226, 228. The pixels are arranged to image a variety of colors byoverlaying the pixels with color-specific microfilters, for example,pixel 222 may image the color red with pixel 224 imaging the color bluewhile pixels 226 and 228 image the color green. The plural pixels offirst pixel group 220 include first pixel 222 and first pixel 222 isoverlaid with first color microfilter 232 (FIG. 9), thus allowing theimaging sensor to image a particular color.

In a variation of this embodiment, the plural pixels of first pixelgroup 220 further include second pixel 224 and second pixel 224 isoverlaid with second color microfilter 234, thus allowing the imagingsensor to image two colors at once. In a further variation of thisembodiment, the plural pixels of first pixel group 220 further includethird pixel 226 or 228 and third pixel 226 or 228 is overlaid with athird color microfilter, e.g., microfilter 232 or 234, thus allowing theimaging sensor to image three colors at once. Those of ordinary skill inthe art will appreciate that overlaying two pixels, e.g., pixels 226 and228, with microfilters of the same color may be desirable to improve theresponse of the imaging sensor to that particular color.

In the situation where, for example, second imaging sensor 16 includesarray 210 of pixel groups 220, second imaging sensor 16 is able to imagemultiple colors, as described previously. Thus, if second imaging sensor16 is imaging two colors by employing a two-pixel group, each pixeloverlaid with a different color microfilter (e.g., red and blue), firstimaging sensor 14 need image only the remaining color (e.g., green).Color selection for first imaging sensor 14 may be accomplished usingfirst color filter 18 disposed along reflected axis 28 between rotatablestructure 100 and first imaging sensor 14. Alternatively, where, forexample, first imaging sensor 14 includes array 210 of pixel groups 220,thus allowing first imaging sensor 14 to image multiple colors, secondimaging sensor 16 need image only the single, remaining color. Colorselection for second imaging sensor 16 may be accomplished using secondcolor filter 20 disposed along direct axis 26 between rotatablestructure 100 and second imaging sensor 16.

In another embodiment, rather than using external color filters 18 and20 to perform single color selection, a color selective coating may beemployed to achieve the same result. For instance, when second imagingsensor 16 includes array 210 of pixel groups 220 and is imaging twocolors, reflection sectors 114 and 118 may be coated with a colorselective coating (such coatings as are known in the optics art and arecommonly used in high quality photography cameras) to provide theremaining color to first imaging sensor 14, as shown in FIGS. 10 and 11.

In FIG. 10, reflection sector 242 is formed from an opaque material,such that no light is transmitted through reflection sector 242, and iscoated with color selective coating 244. Color selective coating 244selects a desired wavelength, i.e., λ1, from the all-band visible lightspectrum that impinges on reflection sector 242 and allows only theselected, desired wavelength to be reflected onto first imaging sensor14. Non-selected wavelengths are absorbed by the opaque material. In analternative embodiment, as illustrated in FIG. 11, reflection sector 246is formed from a transparent material and color selective coating 248allows all wavelengths except for the desired wavelength to betransmitted through the transparent material of reflection sector 246.The desired wavelength, λ1, is reflected onto first imaging sensor 14.In this case, second imaging sensor 16 is operated so that nophotocharge is being accumulated while reflection sector 246 is in thedirect optical path between lens 12 and second imaging sensor 16. Thisis commonly done using exposure control gates or by resetting the sensorjust before an image is to be collected.

FIG. 12 illustrates the situation where first imaging sensor 14 includesarray 210 of pixel groups 220 and is thus imaging multiple colors. Inthis case, second imaging sensor 16 need only image one color, thus,transmission sector 252 is coated with a color selective coating.Transmission sector 252 is formed of a transparent material and iscoated with color selective coating 254. Color selective coating 254selects the desired wavelength, i.e., λ1, from the all-band visiblelight spectrum that impinges on transmission sector 252 and allows onlythe selected, desired wavelength to be transmitted onto second imagingsensor 16. Non-selected wavelengths are reflected away from transmissionsector 252 and towards first imaging sensor 14 that is operated so thatno photocharge is being accumulated while transmission sector 252 is inthe direct optical path between lens 12 and second imaging sensor 16.

As described previously with reference to camera 10 (FIG. 1), firstimaging sensor 14 is disposed to image light that propagates alongreflected axis 28 and second imaging sensor 16 is disposed to imagelight that propagates along direct axis 26. First structure 110 (FIG.2), which serves as rotatable structure 100, includes first and secondtransmission sectors 112 and 116 and first and second reflection sectors114 and 118. In operation, the light that propagates along reflectedaxis 28 is reflected from at least one of reflection sectors 114 and 118and the light that propagates along direct axis 26 passes through atleast one of transmission sectors 112 and 116. In one embodiment, firstreflection sector 114 is coated with a first reflection color selectivecoating, while in another embodiment, first transmission sector 114 iscoated with a first transmission color selective coating, where thereflection and transmission color selective coatings select specificcolor wavelengths, as described previously (FIGS. 10-12).

In the former embodiment, where first reflection sector 114 is coatedwith the first reflection color selective coating, second reflectionsector is coated with a second reflection color selective coating.Additionally, second color filter 20 may be disposed along direct axis26 between rotatable structure 100 and second imaging sensor 16. Thisvariation allows camera 10 to image the requisite three colors sincefirst reflection sector 114 reflects a first color (e.g., red), secondreflection sector 118 reflects a second color (e.g., blue), and secondcolor filter 20 selects a third color (e.g., green) from the light thatpasses through transmission sectors 112 and 116. In a further variationof this embodiment, transmission sectors 112 and 116 are coated with atransmission color selective coating that selects the third color andobviates the need for external second color filter 20.

In the latter embodiment, where first transmission sector 112 is coatedwith the first transmission color selective coating, second transmissionsector 116 is coated with a second transmission color selective coating.Additionally, first color filter 18 may be disposed along reflected axis28 between rotatable structure 100 and first imaging sensor 14. Thisvariation allows camera 10 to image the requisite three colors sincefirst transmission sector 112 transmits a first color (e.g., red),second transmission sector 116 transmits a second color (e.g., blue),and first color filter 18 selects a third color (e.g., green) from thelight that reflects from reflection sectors 114 and 118. In a furthervariation of this embodiment, reflection sectors 114 and 118 are coatedwith a reflection color selective coating that selects the third colorand obviates the need for external first color filter 18.

In another embodiment, both first reflection sector 114 and firsttransmission sector 112 are coated with color selective coatings, withfirst reflection sector 114 being coated with the first reflection colorselective coating and first transmission sector 112 being coated withthe first transmission color selective coating. In one variation on thisembodiment, second transmission sector 116 is also coated with the firsttransmission color selective coating, thus allowing only one color toimpinge on second imaging sensor 16. In another variation, secondreflection sector 118 is also coated with the first reflection colorselective coating, thus allowing only one color to impinge on firstimaging sensor 14.

In a further embodiment, second color filter 20 is disposed along directaxis 26 between rotatable structure 100 and second imaging sensor 16when first reflection sector 114 is coated with the first reflectioncolor selective coating. Alternatively, first color filter 18 isdisposed along reflected axis 28 between rotatable structure 100 andfirst imaging sensor 14 when first transmission sector 112 is coatedwith the first transmission color selective coating.

FIG. 20 illustrates a timing diagram for the operation of firstrotatable structure 110. Timing for the operation of first imagingsensor 14 is denoted generally by reference numeral 1000 and timing forthe operation of second imaging sensor 16 is denoted generally byreference numeral 1050. The operation of first rotatable structure 110is separated into eight regions (denoted by Roman numerals I-VIII) thatcorrespond to the sectors of first rotatable structure 110. The verticalaxes in timing diagrams 1000 and 1050 represents the number of pixelsilluminated in first and second imaging sensors 14 and 16, respectively.The horizontal axes represents the time, or phase, of the rotation offirst rotatable structure 110.

Region I in timing diagram 1000 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 114 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 114 ontofirst imaging sensor 14. As first rotatable structure 110 rotates, firstreflection sector 114 moves out of the objective path of lens 12 whilefirst transmission sector 112 moves into the objective path of lens 12.Fewer pixels of first imaging sensor 14 are illuminated, as shown byregion II in timing diagram 1000. In one embodiment, charge integratesin first imaging sensor 14 only while first imaging sensor 14 is fullyilluminated (bracket 1). In an alternative embodiment, chargeintegration in first imaging sensor 14 begins as first reflection sector114 moves into the objective path of lens 12 and continues as firstreflection sector 114 moves out of the objective path of lens 12 andfewer pixels in first imaging sensor 14 are illuminated (bracket 2).

Once first transmission sector 112 has moved completely into theobjective path of lens 12, the image light no longer reflects onto firstimaging sensor 14, as shown by region III in timing diagram 1000. Chargeis transferred (Xfer 1) from first imaging sensor 14 while firsttransmission sector 112 prevents the image light from impinging on firstimaging sensor 14. The cycle of charge integration in first imagingsensor 14 is repeated as second reflection sector 118 moves into and outof the objective path of lens 12 and the image light reflects fromsecond reflection sector 118 onto first imaging sensor 14 (regionsVI-VI). Charge is again transferred from first imaging sensor 14 oncesecond transmission sector 116 is completely in the objective path oflens 12, thus preventing the image light from impinging on first imagingsensor 14 (region VII). The cycle begins anew as first reflection sector114 moves back into the objective path of lens 12 (region VIII).

Similarly for second imaging sensor 16, timing diagram 1050 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of first transmission sector 112(region II) until the image light passes through a central area of firsttransmission sector 112 such that every pixel on second imaging sensor16 is illuminated (region III). Charge is integrated in second imagingsensor 16 while the image light passes through first transmission sector112 onto second imaging sensor 16. As first rotatable structure 110rotates, first transmission sector 112 moves out of the objective pathof lens 12 while second reflection sector 118 moves into the objectivepath of lens 12. Fewer pixels of second imaging sensor 16 areilluminated, as shown by region IV in timing diagram 1050. In oneembodiment, charge integrates in second imaging sensor 16 only whilesecond imaging sensor 16 is fully illuminated (bracket 1). In analternative embodiment, charge integration in second imaging sensor 16begins as first transmission sector 112 moves into the objective path oflens 12 and continues as first transmission sector 112 moves out of theobjective path of lens 12 (region IV) and fewer pixels in second imagingsensor 16 are illuminated (bracket 2).

Once second reflection sector 118 has moved completely into theobjective path of lens 12, the image light no longer reflects ontosecond imaging sensor 16 (region V). Charge is transferred (Xfer 1) fromsecond imaging sensor 16 while second reflection sector 118 prevents theimage light from impinging on second imaging sensor 16. The cycle ofcharge integration in second imaging sensor 16 is repeated as secondtransmission sector 116 moves into and out of the objective path of lens12 and the image light passes through second transmission sector 116onto second imaging sensor 16 (regions VI-VIII). Charge is againtransferred from second imaging sensor 16 once first reflection sector114 is completely in the objective path of lens 12, thus preventing theimage light from impinging on second imaging sensor 16 (region I). Thecycle begins anew as first transmission sector 112 moves back into theobjective path of lens 12 (region II).

If first and second reflection sectors 114 and 118 are not completelyreflective and if first and second transmission sectors 112 and 116 arenot completely transmissive, imaging sensors 14 and 16 are controlledsuch that neither sensor is capable of integrating charge during thecharge transfer phase of their operation. This type of sensor control iscalled electronic shutter control.

Furthermore, due to the wedge shape of reflection sectors 114 and 118and transmission sectors 112 and 116, the pixels of imaging sensors 14and 16 disposed along the outer radius of first rotatable structure 110will be illuminated for a longer period of time than the pixels disposedalong the inner radius of first rotatable structure 110. The resultingimage may be adjusted in post-processing to allow for the difference inthe amount of charge integrated for different parts of the image. Thepixel values can be weighted allow for normalization of the resultingimage.

Camera with Mechanical Shutter

With reference to second structure 120 (FIG. 3), in operation, the lightthat propagates along reflected axis 28 is reflected from firstreflection sector 122 and the light that propagates along direct axis 26passes through first transmission sector 126. In one embodiment,reflection sector 122 is a mirrored surface such that the light thatimpinges onto first imaging sensor 14 includes the entire spectrum ofvisible light. Similarly, the light that passes through transmissionsector 126 and impinges onto second imaging sensor 16 also includes theentire spectrum of visible light.

In this embodiment, either first imaging sensor 14 or second imagingsensor 16 includes an array 210 of pixel groups, as described previouslywith reference to FIG. 8. First pixel group 220 includes a plurality ofpixels, e.g., pixels 222, 224, 226, 228, that are arranged to image avariety of colors by overlaying the pixels with color-specificmicrofilters. The plural pixels of first pixel group 220 include firstpixel 222 and first pixel 222 is overlaid with first color microfilter232 (FIG. 9), thus allowing the imaging sensor to image a particularcolor.

In a variation of this embodiment, the plural pixels of first pixelgroup 220 further include second pixel 224 and second pixel 224 isoverlaid with second color microfilter 234, thus allowing the imagingsensor to image two colors at once. In a further variation of thisembodiment, the plural pixels of first pixel group 220 further includethird pixel 226 or 228 and third pixel 226 or 228 is overlaid with athird color microfilter, e.g., microfilter 232 or 234, thus allowing theimaging sensor to image three colors at once. Those of ordinary skill inthe art will appreciate that overlaying two pixels, e.g., pixels 226 and228, with microfilters of the same color may be desirable to improve theresponse of the imaging sensor to that particular color.

In the situation where, for example, second imaging sensor 16 includesarray 210 of pixel groups 220, second imaging sensor 16 is able to imagemultiple colors, as described previously. Thus, if second imaging sensor16 is imaging two colors by employing a two-pixel group, each pixeloverlaid with a different color microfilter (e.g., red and blue), firstimaging sensor 14 need image only the remaining color (e.g., green).Color selection for first imaging sensor 14 may be accomplished usingfirst color filter 18 disposed along reflected axis 28 between rotatablestructure 100 and first imaging sensor 14. Alternatively, where, forexample, first imaging sensor 14 includes array 210 of pixel groups 220,thus allowing first imaging sensor 14 to image multiple colors, secondimaging sensor 16 need image only the single, remaining color. Colorselection for second imaging sensor 16 may be accomplished using secondcolor filter 20 disposed along direct axis 26 between rotatablestructure 100 and second imaging sensor 16.

In another embodiment, rather than using external color filters 18 and20 to perform single color selection, a color selective coating may beemployed to achieve the same result. For instance, when second imagingsensor 16 includes array 210 of pixel groups 220 and is imaging twocolors, reflection sector 122 may be coated with a color selectivecoating to provide the remaining color to first imaging sensor 14 (FIGS.10 and 11). In the alternative, when first imaging sensor 14 includesarray 210 of pixel groups 220, first transmission sector 126 is coatedwith a color selective coating to provide the remaining color to secondimaging sensor 16 (FIG. 12).

As described previously with reference to camera 10 (FIG. 1), firstimaging sensor 14 is disposed to image light that propagates alongreflected axis 28 and second imaging sensor 16 is disposed to imagelight that propagates along direct axis 26. Second structure 120 (FIG.3), which serves as rotatable structure 100, includes first reflectionsector 122, first opaque sector 124, and first transmission sector 126.In operation, the light that propagates along reflected axis 28 isreflected from first reflection sectors 122 and the light thatpropagates along direct axis 26 passes through first transmission sector126. In one embodiment, first reflection sector 122 is coated with afirst reflection color selective coating, while in another embodiment,first transmission sector 126 is coated with a first transmission colorselective coating, where the reflection and transmission color selectivecoatings select specific color wavelengths, as described previously(FIGS. 10-12).

In the former embodiment, where first transmission sector 126 is coatedwith the first transmission color selective coating, first imagingsensor 14 includes array 210 of pixel groups 220 (FIG. 8). In the latterembodiment, where first reflection sector 122 is coated with the firstreflection color selective coating, second imaging sensor 16 includesarray 210 of pixel groups 220 (FIG. 8). In either embodiment, firstpixel group 220 includes a plurality of pixels, e.g., pixels 222, 224,226, 228, that are arranged to image a variety of colors by overlayingthe pixels with color-specific microfilters. In these embodiments, theimaging sensor is imaging two particular colors, therefore the pluralpixels of first pixel group 220 includes first pixel 222 that isoverlaid with first color microfilter 232 and second pixel 224 that isoverlaid with second color microfilter 234 (FIG. 9). In a variation ofthese embodiments, the plural pixels of first pixel group 220 furtherinclude a third pixel, pixel 226 or 228, that is overlaid with a thirdcolor microfilter (e.g., 232 or 234), thus allowing the imaging sensorto image a third color.

FIG. 21 illustrates a timing diagram for one embodiment of the operationof second rotatable structure 120. Timing for the operation of firstimaging sensor 14 is denoted generally by reference numeral 1100 andtiming for the operation of second imaging sensor 16 is denotedgenerally by reference numeral 1150. The operation of second rotatablestructure 120 is separated into six regions (denoted by Roman numeralsI-VI) that correspond to the sectors of second rotatable structure 120.The vertical axes in timing diagrams 1100 and 1150 represents the numberof pixels illuminated in first and second imaging sensors 14 and 16,respectively. The horizontal axes represents the time, or phase, of therotation of second rotatable structure 120.

Region I in timing diagram 1100 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 122 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 122 ontofirst imaging sensor 14. As second rotatable structure 120 rotates,first reflection sector 122 moves out of the objective path of lens 12while first transmission sector 126 moves into the objective path oflens 12. Fewer pixels of first imaging sensor 14 are illuminated, asshown by region II in timing diagram 1100. In one embodiment, chargeintegrates in first imaging sensor 14 only while first imaging sensor 14is fully illuminated (bracket 1). In an alternative embodiment, chargeintegration in first imaging sensor 14 begins as first reflection sector122 moves into the objective path of lens 12 and continues as firstreflection sector 122 moves out of the objective path of lens 12 andfewer pixels in first imaging sensor 14 are illuminated (bracket 2).

Similarly for second imaging sensor 16, timing diagram 1150 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of first transmission sector 126(region II) until the image light passes through a central area of firsttransmission sector 126 such that every pixel on second imaging sensor16 is illuminated (region III). Charge is integrated in second imagingsensor 16 while the image light passes through first transmission sector126 onto second imaging sensor 16. As second rotatable structure 120rotates, first transmission sector 126 moves out of the objective pathof lens 12 while first opaque sector 124 moves into the objective pathof lens 12. Fewer pixels of second imaging sensor 16 are illuminated, asshown by region IV in timing diagram 1150. In one embodiment, chargeintegrates in second imaging sensor 16 only while second imaging sensor16 is fully illuminated (bracket 1). In an alternative embodiment,charge integration in second imaging sensor 16 begins as firsttransmission sector 126 moves into the objective path of lens 12 andcontinues as first transmission sector 126 moves out of the objectivepath of lens 12 and fewer pixels in second imaging sensor 16 areilluminated (bracket 2).

Once first opaque sector 124 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto first andsecond imaging sensors 14 and 16, as shown by region V in timing diagram1150. Charge is. transferred (Xfer 1) from both first and second imagingsensors 14 and 16 while first opaque sector 124 prevents the image lightfrom impinging on the imaging sensors 14 and 16. The entire cycle beginsanew as first reflection sector 122 moves back into the objective pathof lens 12, as shown in region VI in timing diagram 1100.

Since first opaque sector 124 is formed of absorbing material, firstopaque sector 124 acts as a light shield under which the imaging sensors14 and 16 can transfer charge without smear. First opaque sector 124acts as a mechanical shutter, thus allowing the imaging sensors 14 and16 to be full-frame transfer type sensors that lack electronic shuttercapabilities. Furthermore, as discussed previously, the wedge shape offirst reflection sector 122 and first transmission sector 126necessitates the adjustment of the resulting image either inpost-processing or by using weighted pixel values.

FIG. 22 illustrates a timing diagram for another embodiment of theoperation of second rotatable structure 120. Timing for the operation offirst imaging sensor 14 is denoted generally by reference numeral 1200and timing for the operation of second imaging sensor 16 is denotedgenerally by reference numeral 1250. The operation of second rotatablestructure 120 is separated into six regions (denoted by Roman numeralsI-VI) that correspond to the sectors of second rotatable structure 120.The vertical axes in timing diagrams 1200 and 1250 represents the numberof pixels illuminated in first and second imaging sensors 14 and 16,respectively. The horizontal axes represents the time, or phase, of therotation of second rotatable structure 120.

Region I in timing diagram 1200 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 122 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 122 ontofirst imaging sensor 14. As second rotatable structure 120 rotates,first reflection sector 122 moves out of the objective path of lens 12while first opaque sector 124 moves into the objective path of lens 12.Fewer pixels of first imaging sensor 14 are illuminated, as shown byregion II in timing diagram 1200. In one embodiment, charge integratesin first imaging sensor 14 only while first imaging sensor 14 is fullyilluminated (bracket 1). In an alternative embodiment, chargeintegration in first imaging sensor 14 begins as first reflection sector122 moves into the objective path of lens 12 and continues as firstreflection sector 122 moves out of the objective path of lens 12 andfewer pixels in first imaging sensor 14 are illuminated (bracket 2).

Once first opaque sector 124 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto first imagingsensor 14, as shown by region III in timing diagram 1200. Charge istransferred (Xfer 1) from first imaging sensor 14 while first opaquesector 124 prevents the image light from impinging on first imagingsensor 14. Alternatively, since light does not again impinge on firstimaging 14 until first reflection sector 122 moves back into theobjective path of lens 12 (region VI), first imaging sensor 14 has alonger charge transfer cycle (Xfer 2), thus allowing first imagingsensor 14 to be a less expensive, lower speed sensor.

Similarly for second imaging sensor 16, timing diagram 1250 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of first transmission sector 126(region IV) until the image light passes through a central area of firsttransmission sector 126 such that every pixel on second imaging sensor16 is illuminated (region V). Charge is integrated in second imagingsensor 16 while the image light passes through first transmission sector126 onto second imaging sensor 16. As second rotatable structure 120rotates, first transmission sector 126 moves out of the objective pathof lens 12 while first reflection sector 122 moves into the objectivepath of lens 12. Fewer pixels of second imaging sensor 16 areilluminated, as shown by region VI in timing diagram 1250. In oneembodiment, charge integrates in second imaging sensor 16 only whilesecond imaging sensor 16 is fully illuminated (bracket 1). In analternative embodiment, charge integration in second imaging sensor 16begins as first transmission sector 126 moves into the objective path oflens 12 and continues as first transmission sector 126 moves out of theobjective path of lens 12 and fewer pixels in second imaging sensor 16are illuminated (bracket 2).

Once first reflection sector 122 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto second imagingsensor 16, as shown by region I in timing diagram 1250. Charge istransferred (Xfer 1) from second imaging sensor 16 while firstreflection sector 122 prevents the image light from impinging on secondimaging sensor 16. Alternatively, since light does not again impinge onsecond imaging 16 until first transmission sector 126 moves back intothe objective path of lens 12 (region IV), second imaging sensor 16 hasa longer charge transfer cycle (Xfer 2), thus allowing second imagingsensor 16 to be a less expensive, lower speed sensor. The entire cyclebegins anew with charge integration in first imaging sensor 14 as firstreflection sector 122 moves back into the objective path of lens 12, asshown in region VI in timing diagram 1200.

Since first opaque sector 124 is formed of absorbing material, firstopaque sector 124 acts as a light shield under which second imagingsensor 16 can transfer charge without smear. In this embodiment, firstreflection sector 122 is made of material that prevents any transmissionof image light onto second imaging sensor 16 while first reflectionsector 122 is in the objective path of lens 12. Therefore both firstopaque sector 124 and first reflection sector 122 act as mechanicalshutters, thus allowing the imaging sensors 14 and 16 to be full-frametransfer type sensors that lack electronic shutter capabilities.Furthermore, as discussed previously, the wedge shape of firstreflection sector 122 and first transmission sector 126 necessitates theadjustment of the resulting image either in post-processing or by usingweighted pixel values.

In FIG. 4, third structure 130 is a variation of second structure 120that further includes second reflection sector 138 disposed adjacent tofirst transmission sector 136 and second transmission sector 140disposed adjacent to second reflection sector 138. Third structure 130may also include counterweight 142, which serves to offset the massdistribution differential caused by transmission sectors 136 and 140when transmission sectors 136 and 140 are air-filled gaps, thuspreserving dynamic balance in third structure 130. As noted previously,the dynamic balancing function of third structure 130 may be achieved byother means, for example, relocating the placement of axle attachmentpoint 22 to create a dynamically balanced rotatable structure. In someembodiments, each sector subtends one-fifth of a circle. Otherembodiments may vary as described further herein.

In one embodiment, first reflection sector 132 is coated with a firstreflection color selective coating, while in another embodiment, firsttransmission sector 136 is coated with a first transmission colorselective coating, where the reflection and transmission color selectivecoatings select specific color wavelengths, as described previously(FIGS. 10-12). In the former embodiment, where first reflection sector132 is coated with the first reflection color selective coating, secondreflection sector 142 is coated with a second reflection color selectivecoating. Additionally, second color filter 20 may be disposed alongdirect axis 26 between rotatable structure 100 and second imaging sensor16. This variation allows camera 10 to image the requisite three colorssince first reflection sector 132 reflects a first color (e.g., red),second reflection sector 138 reflects a second color (e.g., blue), andsecond color filter 20 selects a third color (e.g., green) from thelight that passes through transmission sectors 136 and 140. In a furthervariation of this embodiment, transmission sectors 136 and 140 arecoated with a transmission color selective coating that selects thethird color and obviates the need for external second color filter 20.

In the latter embodiment, where first transmission sector 136 is coatedwith the first transmission color selective coating, second transmissionsector 140 is coated with a second transmission color selective coating.Additionally, first color filter 18 may be disposed along the reflectedaxis between rotatable structure 100 and first imaging sensor 14. Thisvariation allows camera 10 to image the requisite three colors sincefirst transmission sector 136 transmits a first color (e.g., red),second transmission sector 140 transmits a second color (e.g., blue),and first color filter 18 selects a third color (e.g., green) from thelight that reflects from reflection sectors 132 and 138. In a furthervariation of this embodiment, reflection sectors 132 and 138 are coatedwith a reflection color selective coating that selects the third colorand obviates the need for external first color filter 18.

In another embodiment, both first reflection sector 132 and firsttransmission sector 136 are coated with color selective coatings, withfirst reflection sector 132 being coated with the first reflection colorselective coating and first transmission sector 136 being coated withthe first transmission color selective coating. In one variation on thisembodiment, second transmission sector 140 is also coated with the firsttransmission color selective coating, thus allowing only one color toimpinge on second imaging sensor 16. In another variation, secondreflection sector 138 is also coated with the first reflection colorselective coating, thus allowing only one color to impinge on firstimaging sensor 14.

In a further embodiment, second color filter 20 is disposed along directaxis 26 between rotatable structure 100 and second imaging sensor 16when first reflection sector 132 is coated with the first reflectioncolor selective coating. Alternatively, first color filter 18 isdisposed along reflected axis 28 between rotatable structure 100 andfirst imaging 14 sensor when first transmission sector 136 is coatedwith the first transmission color selective coating.

FIG. 23 illustrates a timing diagram for the operation of thirdrotatable structure 130. Timing for the operation of first imagingsensor 14 is denoted generally by reference numeral 1300 and timing forthe operation of second imaging sensor 16 is denoted generally byreference numeral 1350. The operation of third rotatable structure 130is separated into ten regions (denoted by Roman numerals I-X) thatcorrespond to the sectors of third rotatable structure 130. The verticalaxes in timing diagrams 1300 and 1350 represents the number of pixelsilluminated in first and second imaging sensors 14 and 16, respectively.The horizontal axes represents the time, or phase, of the rotation ofthird rotatable structure 130.

Region I in timing diagram 1300 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 132 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 132 ontofirst imaging sensor 14. As third rotatable structure 130 rotates, firstreflection sector 132 moves out of the objective path of lens 12 whilefirst opaque sector 134 moves into the objective path of lens 12. Fewerpixels of first imaging sensor 14 are illuminated, as shown by region IIin timing diagram 1300. In one embodiment, charge integrates in firstimaging sensor 14 only while first imaging sensor 14 is fullyilluminated (bracket 1). In an alternative embodiment, chargeintegration in first imaging sensor 14 begins as first reflection sector132 moves into the objective path of lens 12 and continues as firstreflection sector 132 moves out of the objective path of lens 12 andfewer pixels in first imaging sensor 14 are illuminated (bracket 2).

Once first opaque sector 134 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto first imagingsensor 14, as shown by region III in timing diagram 1300. Charge istransferred (Xfer 1) from first imaging sensor 14 while first opaquesector 134 prevents the image light from impinging on first imagingsensor 14.

Similarly for second imaging sensor 16, timing diagram 1350 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of first transmission sector 136(region IV) until the image light passes through a central area of firsttransmission sector 136 such that every pixel on second imaging sensor16 is illuminated (region V). Charge is integrated in second imagingsensor 16 while the image light passes through first transmission sector136 onto second imaging sensor 16. As third rotatable structure 130rotates, first transmission sector 136 moves out of the objective pathof lens 12 while second reflection sector 138 moves into the objectivepath of lens 12. Fewer pixels of second imaging sensor 16 areilluminated, as shown by region VI in timing diagram 1350. In oneembodiment, charge integrates in second imaging sensor 16 only whilesecond imaging sensor 16 is fully illuminated (bracket 1). In analternative embodiment, charge integration in second imaging sensor 16begins as first transmission sector 136 moves into the objective path oflens 12 and continues as first transmission sector 136 moves out of theobjective path of lens 12 and fewer pixels in second imaging sensor 16are illuminated (bracket 2).

Once second reflection sector 138 has moved completely into theobjective path of lens 12, the image light no longer reflects ontosecond imaging sensor 16, as shown by region VII in timing diagram 1350.Charge is transferred (Xfer 1) from second imaging sensor 16 while firstreflection sector 132 prevents the image light from impinging on secondimaging sensor 16.

The cycle of charge integration in first imaging sensor 14 is repeatedas second reflection sector 138 moves into and out of the objective pathof lens 12 and the image light reflects from second reflection sector138 onto first imaging sensor 14, as shown in regions VI-VIII in timingdiagram 1300. Charge is again transferred from first imaging sensor 14once second transmission sector 140 is completely in the objective pathof lens 12, thus preventing the image light from impinging on firstimaging sensor 14 (region IX).

The cycle of charge integration in second imaging sensor 16 is repeatedas second transmission sector 140 moves into and out of the objectivepath of lens 12 and the image light passes through second transmissionsector 140 onto second imaging sensor 16, as shown in regions VIII-X intiming diagram 1350. Charge is again transferred from second imagingsensor 16 once first reflection sector 132 is completely in theobjective path of lens 12, thus preventing the image light fromimpinging on second imaging sensor 16 (region I). The entire cyclebegins anew as first reflection sector 132 moves back into the objectivepath of lens 12 (region X).

Since first opaque sector 134 is formed of absorbing material, firstopaque sector 134 acts as a light shield under which second imagingsensor 16 can transfer charge without smear. In this embodiment, firstand second reflection sectors 132 and 138 are made of material thatprevents any transmission of image light onto second imaging sensor 16while the reflection sectors 132 and 138 are in the objective path oflens 12. Therefore both first opaque sector 134 and the reflectionsectors 132 and 138 act as mechanical shutters, thus allowing theimaging sensors 14 and 16 to be full-frame transfer type sensors thatlack electronic shutter capabilities. Furthermore, as discussedpreviously, the wedge shape of first reflection sector 132 and firsttransmission sector 136 necessitates the adjustment of the resultingimage either in post-processing or by using weighted pixel values.

In FIG. 5, fourth structure 150 is another variation of second structure120 that further includes second opaque sector 158 disposed adjacent tofirst transmission sector 156, second reflection sector 160 disposedadjacent to second opaque sector 158, and third opaque sector 162disposed adjacent to second reflection sector 160. Fourth structure 150may also include counterweights 164 and 165, which serve to offset themass distribution differential caused by first transmission sector 156when first transmission sector 156 is an air-filled gap, thus preservingdynamic balance in fourth structure 150. As noted previously, thedynamic balancing function of fourth structure 150 may be achieved byother means, for example, relocating the placement of axle attachmentpoint 22 to create a dynamically balanced rotatable structure. In someembodiments, each sector subtends one-sixth of a circle. Otherembodiments may vary as described further herein. In operation, thelight that propagates along direct axis 26 passes through firsttransmission sector 156 and the light that propagates along reflectedaxis 28 is reflected from reflection sectors 152 and 160.

FIG. 24 illustrates a timing diagram for the operation of fourthrotatable structure 150. Timing for the operation of first imagingsensor 14 is denoted generally by reference numeral 1400 and timing forthe operation of second imaging sensor 16 is denoted generally byreference numeral 1450. The operation of fourth rotatable structure 150is separated into twelve regions (denoted by Roman numerals I-XII) thatcorrespond to the sectors of fourth rotatable structure 150. Thevertical axes in timing diagrams 1400 and 1450 represents the number ofpixels illuminated in first and second imaging sensors 14 and 16,respectively. The horizontal axes represents the time, or phase, of therotation of fourth rotatable structure 150.

Region I in timing diagram 1400 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 152 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 152 ontofirst imaging sensor 14. As fourth rotatable structure 150 rotates,first reflection sector 152 moves out of the objective path of lens 12while first opaque sector 154 moves into the objective path of lens 12.Fewer pixels of first imaging sensor 14 are illuminated, as shown byregion II in timing diagram 1400. In one embodiment, charge integratesin first imaging sensor 14 only while first imaging sensor 14 is fullyilluminated (bracket 1). In an alternative embodiment, chargeintegration in first imaging sensor 14 begins as first reflection sector152 moves into the objective path of lens 12 and continues as firstreflection sector 152 moves out of the objective path of lens 12 andfewer pixels in first imaging sensor 14 are illuminated (bracket 2).

Once first opaque sector 154 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto first imagingsensor 14, as shown by region III in timing diagram 1400. Charge istransferred (Xfer 1) from first imaging sensor 14 while first opaquesector 154 prevents the image light from impinging on first imagingsensor 14.

Similarly for second imaging sensor 16, timing diagram 1450 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of first transmission sector 156(region IV) until the image light passes through a central area of firsttransmission sector 156 such that every pixel on second imaging sensor16 is illuminated (region V). Charge is integrated in second imagingsensor 16 while the image light passes through first transmission sector156 onto second imaging sensor 16. As fourth rotatable structure 150rotates, first transmission sector 156 moves out of the objective pathof lens 12 while second opaque sector 158 moves into the objective pathof lens 12. Fewer pixels of second imaging sensor 16 are illuminated, asshown by region VI in timing diagram 1450. In one embodiment, chargeintegrates in second imaging sensor 16 only while second imaging sensor16 is fully illuminated (bracket 1). In an alternative embodiment,charge integration in second imaging sensor 16 begins as firsttransmission sector 156 moves into the objective path of lens 12 andcontinues as first transmission sector 156 moves out of the objectivepath of lens 12 and fewer pixels in second imaging sensor 16 areilluminated (bracket 2).

Once second opaque sector 158 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto second imagingsensor 16, as shown by region VII in timing diagram 1450. Charge istransferred (Xfer 1) from second imaging sensor 16 while secondreflection sector 158 prevents the image light from impinging on secondimaging sensor 16.

The cycle of charge integration in first imaging sensor 14 is repeatedas second reflection sector 160 moves into and out of the objective pathof lens 12 and the image light reflects from second reflection sector160 onto first imaging sensor 14, as shown in regions VIII-X in timingdiagram 1400. Charge is again transferred from first imaging sensor 14once third opaque sector 162 is completely in the objective path of lens12, thus preventing the image light from impinging on first imagingsensor 14 (region XI). The entire cycle begins anew as first reflectionsector 152 moves back into the objective path of lens 12 (region XII).

Since first, second, and third opaque sectors 154, 158, and 162 areformed of absorbing material, the opaque sectors 154, 158, and 162 actas a light shield under which first and second imaging sensors 14 and 16can transfer charge without smear. The opaque sectors 154, 158, and 162act as mechanical shutters, thus allowing the imaging sensors 14 and 16to be full-frame transfer type sensors that lack electronic shuttercapabilities. Furthermore, as discussed previously, the wedge shape ofthe reflection sectors 152 and 160 and first transmission sector 156necessitates the adjustment of the resulting image either inpost-processing or by using weighted pixel values.

In FIG. 6, fifth structure 170 is a further variation of secondstructure 120 that further includes second opaque sector 178 disposedadjacent to first transmission sector 176, second transmission sector180 disposed adjacent to second opaque sector 178, and third opaquesector 182 disposed adjacent to second transmission sector 180. Fifthstructure 170 may also include counterweight 184, which serves to offsetthe mass distribution differential caused by transmission sectors 176and 180 when transmission sectors 176 and 180 are air-filled gap, thuspreserving dynamic balance in fifth structure 170. As noted previously,the dynamic balancing function of fifth structure 170 may be achieved byother means, for example, relocating the placement of axle attachmentpoint 22 to create a dynamically balanced rotatable structure. In someembodiments, each sector subtends one-sixth of a circle. Otherembodiments may vary as described further herein. In operation, thelight that propagates along direct axis 26 passes through transmissionsectors 176 and 180 and the light that propagates along reflected axis28 is reflected from first reflection sector 172.

FIG. 25 illustrates a timing diagram for the operation of fifthrotatable structure 170. Timing for the operation of first imagingsensor 14 is denoted generally by reference numeral 1500 and timing forthe operation of second imaging sensor 16 is denoted generally byreference numeral 1550. The operation of fifth rotatable structure 170is separated into twelve regions (denoted by Roman numerals I-XII) thatcorrespond to the sectors of fifth rotatable structure 170. The verticalaxes in timing diagrams 1500 and 1550 represents the number of pixelsilluminated in first and second imaging sensors 14 and 16, respectively.The horizontal axes represents the time, or phase, of the rotation offifth rotatable structure 170.

Region I in timing diagram 1500 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 172 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 172 ontofirst imaging sensor 14. As fifth rotatable structure 170 rotates, firstreflection sector 172 moves out of the objective path of lens 12 whilefirst opaque sector 174 moves into the objective path of lens 12. Fewerpixels of first imaging sensor 14 are illuminated, as shown by region IIin timing diagram 1500. In one embodiment, charge integrates in firstimaging sensor 14 only while first imaging sensor 14 is fullyilluminated (bracket 1). In an alternative embodiment, chargeintegration in first imaging sensor 14 begins as first reflection sector172 moves into the objective path of lens 12 and continues as firstreflection sector 172 moves out of the objective path of lens 12 andfewer pixels in first imaging sensor 14 are illuminated (bracket 2).

Once first opaque sector 174 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto first imagingsensor 14, as shown by region III in timing diagram 1500. Charge istransferred (Xfer 1) from first imaging sensor 14 while first opaquesector 174 prevents the image light from impinging on first imagingsensor 14.

Similarly for second imaging sensor 16, timing diagram 1550 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of first transmission sector 176(region IV) until the image light passes through a central area of firsttransmission sector 176 such that every pixel on second imaging sensor16 is illuminated (region V). Charge is integrated in second imagingsensor 16 while the image light passes through first transmission sector176 onto second imaging sensor 16. As fifth rotatable structure 170rotates, first transmission sector 176 moves out of the objective pathof lens 12 while second opaque sector 178 moves into the objective pathof lens 12. Fewer pixels of second imaging sensor 16 are illuminated, asshown by region VI in timing diagram 1550. In one embodiment, chargeintegrates in second imaging sensor 16 only while second imaging sensor16 is fully illuminated (bracket 1). In an alternative embodiment,charge integration in second imaging sensor 16 begins as firsttransmission sector 176 moves into the objective path of lens 12 andcontinues as first transmission sector 176 moves out of the objectivepath of lens 12 and fewer pixels in second imaging sensor 16 areilluminated (bracket 2).

Once second opaque sector 178 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto second imagingsensor 16, as shown by region VII in timing diagram 1550. Charge istransferred (Xfer 1) from second imaging sensor 16 while secondreflection sector 158 prevents the image light from impinging on secondimaging sensor 16.

The cycle of charge integration in second imaging sensor 16 is repeatedas second transmission sector 180 moves into and out of the objectivepath of lens 12 and the image light reflects from second transmissionsector 180 onto second imaging sensor 16, as shown in regions VIII-X intiming diagram 1550. Charge is again transferred from second imagingsensor 16 once third opaque sector 182 is completely in the objectivepath of lens 12, thus preventing the image light from impinging onsecond imaging sensor 16 (region XI). The entire cycle begins anew asfirst reflection sector 172 moves back into the objective path of lens12, as shown in region XII in timing diagram 1500.

Since first, second, and third opaque sectors 174, 178, and 182 areformed of absorbing material, the opaque sectors 174, 178, and 182 actas a light shield under which first and second imaging sensors 14 and 16can transfer charge without smear. The opaque sectors 174, 178, and 182act as mechanical shutters, thus allowing the imaging sensors 14 and 16to be full-frame transfer type sensors that lack electronic shuttercapabilities. Furthermore, as discussed previously, the wedge shape ofthe reflection sectors 152 and 160 and first transmission sector 176necessitates the adjustment of the resulting image either inpost-processing or by using weighted pixel values.

Color Post-Processing

As mentioned previously, a minimum of three colors (red, blue, andgreen) are necessary to create a color image. It is not necessary,however, to overlay the imaging sensors with a microfiltered array, toemploy color selective coatings, or a combination of both to obtainthese three colors directly. Rather, it is possible to obtain only twocolor images and an all-band image and use a post-processing procedureto obtain the third color.

For example, in an alternative embodiment with reference to firststructure 110 (FIG. 2), first imaging sensor 14 includes array 210 ofpixel groups 220, where first pixel group 220 includes only first pixel222 and second pixel 224, which are overlaid with first colormicrofilter 232 and second color microfilter 234 (FIG. 9). In this case,first imaging sensor 14 only images two colors. To obtain the thirdcolor, either: (1) transmission sectors 112 and 116 might be overlaidwith a color selective filter or (2) color filter 20 might be placed inthe direct path, along direct axis 26 between rotatable structure 100and second imaging sensor 16.

However, in this alternative embodiment, the third color is obtainedwithout imposing such mechanical strictures. FIG. 19 illustrates amethod for obtaining the third color through post-processing. If nocoatings are placed on transmission sectors 112 and/or 116 and colorfilter 20 is not used, second imaging sensor 16 will receive theall-band (to which the sensor responds) visible light spectrum (A) thatpasses through transmission sectors 112 and 116, denoted by referencenumeral 500. Sensor 16 converts the all-band image light intocorresponding all-band electrical image data.

The two microfilters overlying first imaging sensor 14, in this example,pass through to a first imaging sensor 14 the two spectra (B), denotedby reference numerals 510 and 512. Spectra 510 and 512 are converted byfirst imaging sensor 14 into electrical image data. The selectedtwo-color spectra (B) (510, 512) is subtracted in post-processingelectronics from all-band spectrum 500 through post-processing to obtainthe third spectra (A-B), denoted by reference numeral 520. In thepost-processing electronics, the all-band image 500 is represented by anarray of pixel values that are output from sensor 16. In thepost-processing electronics, a first selected spectra 510 is representedby another array of pixel values that are interpolated fromcorresponding pixels output from sensor 14, and a second selectedspectra 512 is represented by a third array of pixel values that areinterpolated from corresponding pixels output from sensor 14. The secondarray (corresponding to spectrum 510) and the third array (correspondingto spectrum 512) are subtracted from the first array (corresponding tothe all-band spectrum 500), on a pixel by pixel basis, to provide thearray corresponding to the third spectral component 520. This method canbe employed in any of the situations described herein where all-bandspectrum 500 is received by one imaging sensor and selected spectra 510and 512 are received by the other imaging sensor.

Choppered-Wheel

In another embodiment, camera 10 is a 2-chip cinematography camera thatemploys two sensors, for example, a color and monochrome sensorpositioned at the respective focal planes of an optical system (FIG. 1).That might be accomplished by positioning a sensor, e.g., second imagingsensor 16, in the film plane, along direct axis 26, and another sensor,e.g., first imaging sensor 14, at the plane of the viewfinder, alongreflected axis 28, of a traditional 35 mm film based motion picturecamera.

In a traditional film based cinematography camera there is only oneimage capture area—the film plane. In this case, a rotating mirror isused to shutter the film during film transport between frames, and atthe same time, to divert the image to a ground glass viewfinder. Whenthe rotating mirror is located at the exit pupil of lens 12, the imageis reflected onto the ground glass viewfinder while the film in the filmgate is being moved to a new position. Then, when the rotating mirrormoves away from the exit pupil of lens 12, the image is projectedthrough the mirror onto the film which had been first positioned in thefilm gate and then second brought to a stop to be not moving duringexposure to light.

In the present embodiment, the sensors will convert the variations inlight intensity to electrical signals in each of many pixels. In a CCDtype sensor, the signal charge captured by the pixels is transferredthrough other light sensitive pixels before they reach a storage area ora readout device on the sensor. Thus, it is important that this transfertake place in darkness. If these light sensitive pixels are illuminatedduring the transfer, the signal will be contaminated by additional“smear” signal charge. To avoid image smear, the sensors must not beilluminated during transfer of the image from the sensor image area tothe storage or readout area.

In a 2-chip camera employing two image sensors, the traditional methodas used in 35 mm film based cameras could be used to prevent smear. Forexample, the electronic image is read out from one sensor (e.g., sensor14, FIG. 1) while it is in darkness and the image light passes to theother sensor and an image is being collected in the other sensor (e.g.,sensor 16). However, the two sensors would not be exposedsimultaneously, and a lack of simultaneous exposure could lead toundesirable artifacts in the video images as viewed later.

Alternatively, a beam splitter could be used to split the light betweenthe two sensors and allow them to be exposed simultaneously. However,there would be no shutter action. Image smear would not be preventedunless a technology, such as used in interline transfer sensors, were tobe used. Such ILT sensors reduce the fill factor and reduce sensorsensitivity. The use of both a rotating mirror and a beam splitter isprecluded for geometrical reasons when the use of existing industrystandard optical components (e.g., film gate and lenses for industrystandard cinematography cameras) is desired. In a 2-chip camera, it isdesirable to employ a methodology that prevents image smear and allowssimultaneous image capture by two sensors through the same objectivelens.

FIG. 7 illustrates a choppered-wheel rotatable structure that allows atime average simultaneous exposure of the two image sensors using anovel segmented rotating mirror. Choppered-wheel 190 is a variation ofsecond structure 120 that further includes second reflection sector 198as in structure 130 (FIG. 4) disposed adjacent to first transmissionsector 196 and second transmission sector 200 disposed adjacent tosecond reflection sector 198. Additionally, choppered-wheel 190 mayfurther include third reflection sector 202 disposed adjacent to secondtransmission sector 200 and third transmission sector 204 disposedadjacent to third reflection sector 202 as in structure 190 (FIG. 7). Inother embodiments, additional alternating reflection and transmissionsectors might be used. Choppered-wheel 190 is designed such that the sumof the angular extents of the sectors for all the reflection sectors(e.g., 192, 198, and 202) is made equal to the angular extent of thesectors for all the transmission sectors (e.g., 196, 200, and 204) whenthe total exposure for both imaging sensors 14 and 16 is to be equal.

In a variant embodiment, when one sensor has an overlying color filterarray (FIG. 8) or an intervening external color filter (e.g., colorfilters 18 or 20) which reduces the total amount of light reaching thesensor, an improvement in the total system dynamic range may be achievedby increasing the relative exposure for the sensor that has filterlosses relative to the sensor that does not. The ratio of theirexposures is determined such as to optimize the system dynamic range. Inthis case, choppered-wheel 190 is designed such that the ratio of thesum of the angular extents of the sectors for all the reflection sectors(e.g., 192, 198, and 202) to the sum of the angular extents of thesectors for all the transmission sectors (e.g., 196, 200, and 204) willbe equal to the ratio of the desired exposures of the two sensors.

Choppered-wheel 190 may also include counterweights 206 and 207, whichserve to offset the mass distribution differential caused by thetransmission sectors 196, 200, and 204 when the transmission sectors areair-filled gaps, thus preserving dynamic balance in choppered-wheel 190.Where further transmission sectors are included, the counterweightlocation is adjusted as necessary to preserve dynamic balance inchoppered-wheel 190. As noted previously, the dynamic balancing functionof choppered-wheel 190 may be achieved by other means, for example,relocating the placement of axle attachment point 22 to create adynamically balanced rotatable structure.

In operation, the light entering lens 12 will be directed by thereflection sectors (e.g., 192, 198, and 202) to first imaging sensor 14to the exclusion of second imaging sensor 16. Likewise, the lightallowed to pass through the transmission sectors (e.g., 196, 200, and204) to second imaging sensor 16 will not be detected by first imagingsensor 14. First opaque sector 194 acts as a shutter that prevents lightfrom reaching either imaging sensors. The physical geometry (i.e.,FIG. 1) enabling this operation is preferably made to be the same asused in a traditional 35 mm film based cinematography camera.

Imaging sensors 14 and 16 are operated with timing control such thatwhen first opaque sector 194 is positioned at the exit pupil of lens 12,the charge transfer operation of both imaging sensors 14 and 16 isperformed. The angular extent of this region of the structure 190 isdesigned such that the imaging sensors remain in darkness for a time atleast as long as required to affect the transfer of an image to storageareas of sensors 14 and 16 or transfer out through a readout register.The wheel rotates uniformly at the frame rate. First opaque sector 194must be large enough to provide blanking over the range of frame ratesanticipated for camera 10.

Imaging sensors 14 and 16 are further operated with timing control suchthat the two sensors are integrating signal charge once per rotation ofchoppered-wheel structure 190 and will receive light from the scene thatis divided into a number of discrete intervals by the segments ofchoppered-wheel 190. The net result of the rotation of thechoppered-wheel structure 190 is to ensure that during integration, theimaging sensors achieve a time averaged near simultaneous capture of theimage. For example, the image will be projected alternately onto firstimaging sensor 14 and then onto second imaging sensor 16 as many timesas the reflection and transmission sectors provide (e.g., three times inFIG. 7). Note that the center of exposure of all transmission sectors inFIG. 7 is the center of second transmission sector 200. The center ofthe exposure of all refection sectors in FIG. 7 is the center of thirdreflection sector 202. Thus, the center of the exposure of sensors 14and 16 are separated by the time it takes to rotate through the angularextent of about one sector. A structure 190 having additional chopperedsectors will have exposure time centers even closer.

A variant design (not shown) omits first opaque sector 194. Instead,each imaging sensor is read out in darkness during the last segment ofthe revolution of choppered-wheel 190 in which the other imaging sensoris illuminated. In this variant, the image information from the firstimaging sensor 14 to be read out is then buffered in an internal lightshielded memory or in an external memory. The memory buffered image isthen read out concurrently with the non-memory buffered image fromsecond imaging sensor 16 so that the same pixel in each image is fed tofurther processing concurrently.

In alternative embodiments, the light reflected to first imaging sensor14 is imaged as a monochrome image or a microfiltered pixel array colorimage (FIGS. 8 and 9). In array 210 pattern, four pixels (222, 224, 226,and 228) in a rectangular group 220 are imaged together. For example,one pixel is covered with a red microfilter; another pixel is coveredwith a blue microfilter; and the last two pixels are covered with greenmicrofilters. Alternative filter color selections might be chosen.

In a modified array 210 pattern in one of imaging sensor 14 or 16, twopixels in pixel group 220 are covered with microfilters. For example,one pixel is covered with a red microfilter, and the other pixel iscovered with a blue microfilter. The other of imaging sensor 14 or 16images either the third color (e.g., green) or all-band spectra fromwhich the third color can be derived. The outputs from imaging sensors14 and 16 either provide three colors or are processed to regenerate athree color image. For example, brightness is sensed by second imagingsensor 16 two colors are sensed by the two-color microfilters of firstimaging sensor 14. The third color is developed from processingbrightness using second imaging sensor 16 and the two colors from firstimaging sensor 14. Variants may be made using different ways toreconstruct the primary colors.

A special coating (e.g., FIG. 10) may be applied to the reflectionsectors of choppered-wheel 190 to filter out undesired wavelengths. Forexample, the removal of near IR wavelengths to improve color fidelitywhen first imaging sensor 14 employs color filters which may havetransmission in the near IR, as is a good case for monolithic filters.

FIG. 26 illustrates a timing diagram for the operation ofchoppered-wheel 190. Timing for the operation of first imaging sensor 14is denoted generally by reference numeral 1600 and timing for theoperation of second imaging sensor 16 is denoted generally by referencenumeral 1650. The operation of choppered-wheel 190 is separated intofourteen regions (denoted by Roman numerals I-XIV) that correspond tothe sectors of choppered-wheel 190. The vertical axes in timing diagrams1600 and 1650 represents the number of pixels illuminated in first andsecond imaging sensors 14 and 16, respectively. The horizontal axesrepresents the time, or phase, of the rotation of choppered-wheel 190.

Region I in timing diagram 1600 shows the charge integration in firstimaging sensor 14 while the image light reflects from a central area offirst reflection sector 192 such that every pixel on first imagingsensor 14 is illuminated. Charge is integrated in first imaging sensor14 while the image light reflects from first reflection sector 192 ontofirst imaging sensor 14. As choppered-wheel 190 rotates, firstreflection sector 192 moves out of the objective path of lens 12 whilethird transmission sector 204 moves into the objective path of lens 12.Fewer pixels of first imaging sensor 14 are illuminated, as shown byregion II in timing diagram 1600. In the present embodiment, the imagingsensors 14 and 16 are operated to accumulate photo charge over a timeperiod that extends over multiple reflection and transmission sectors(bracket 3). First imaging sensor 14 is operated to accumulate photocharge over regions I-X and XIV of timing diagram 1600. Second imagingsensor 16 is operated to accumulate photo charge over regions II-XI oftiming diagram 1650. However, due to the design of choppered-wheel 190,first imaging sensor 14 actually converts light to electrical signal(accumulated in the sensor) over only regions I-II, IV-VI, VIII-X andXIV of timing diagram 1600. During regions III and VII, first imagingsensor 14 is in darkness inside of the camera body. During regions I, Vand IX, first imaging sensor 14 is fully illuminated, and during regionsII, IV, VI, VIII, X and XIV, first imaging sensor 14 is partiallyilluminated. The center of region V is the center of the exposureinterval of first imaging sensor 14.

Similarly for second imaging sensor 16, timing diagram 1650 shows thecharge integration in second imaging sensor 16 while the image lightpasses through an increasing portion of third transmission sector 204(region II) until the image light passes through a central area of thirdtransmission sector 204 such that every pixel on second imaging sensor16 is illuminated (region III). Charge is integrated in second imagingsensor 16 while the image light passes through third transmission sector204 onto second imaging sensor 16. As choppered-wheel 190 rotates, thirdtransmission sector 204 moves out of the objective path of lens 12 whilethird reflection sector 202 moves into the objective path of lens 12.Fewer pixels of second imaging sensor 16 are illuminated, as shown byregion IV in timing diagram 1650. Due to the design of choppered-wheel190, second imaging sensor 16 actually converts light to electricalsignal (accumulated in the sensor) over only regions II-IV, VI-VIII andX-XII of timing diagram 1650. During regions V and IX, second imagingsensor 16 is in darkness inside of the camera body. During regions III,VII and XI, second imaging sensor 16 is fully illuminated, and duringregions II, IV, VI, VIII, X and XII, second imaging sensor 16 ispartially illuminated. The center of region VII is the center of theexposure interval of second imaging sensor 16.

Thus, the difference in the center of the exposure intervals of firstand second imaging sensors 14 and 16 is the time between the center ofregion V (timing diagram 1600) and the center of region VII (timingdiagram 1650). Choppered-wheel 190 may be designed to include many morechopped sectors to narrow the time difference between the centers of theexposures of first and second imaging sensor 14 and 16 to minimized anyartifacts that may be caused by differences in exposure times.

Once first opaque sector 194 has moved completely into the objectivepath of lens 12, the image light no longer reflects onto first andsecond imaging sensor 14 and 16, as shown by region XIII in timingdiagrams 1600 and 1650. Charge is transferred (Xfer 1) from both firstand second imaging sensors 14 and 16 while first opaque sector 194prevents the image light from impinging on the imaging sensors 14 and16. The entire cycle begins anew as first reflection sector 192 movesback into the objective path of lens 12, as shown in region XIV intiming diagram 1600.

Since first opaque sector 194 is formed of absorbing material, firstopaque sector 194 acts as a light shield under which the imaging sensors14 and 16 can transfer charge without smear. First opaque sector 194acts as a mechanical shutter, thus allowing the imaging sensors 14 and16 to be full-frame transfer type sensors that lack electronic shuttercapabilities. Furthermore, as discussed previously, the wedge shape offirst reflection sector 192 and first transmission sector 196necessitates the adjustment of the resulting image either inpost-processing or by using weighted pixel values.

Improved Blue/Green Response

In general, the physics of many solid state sensors (CCD or CMOS) of thepreferred type causes the sensor to be more sensitive to red light thanto blue light. Short wavelengths, such as blue and ultraviolet, areattenuated quickly in upper layers of poly-crystalline silicon that arefrequently used in photogates of a frame transfer sensor. Similarly, thehuman eye is more sensitive to green light, which lies in the middle ofthe visible light spectrum, than to any other wavelength, or color, ofvisible light. Therefore, in many applications, it is desirable to makea camera that is more sensitive to at least one of blue and green lightin order to satisfy these two considerations and/or that adjusts colorsensitivities to match the color response of the intended display (e.g.,computer monitor, television, projector).

In FIG. 13, sixth structure 300 is a variation of first structure 110 inwhich first reflection sector 304 and second reflection sector 308 areeach characterized by a corresponding angular extent and the angularextent of first reflection sector 304 is unequal to the angular extentof second reflection sector 308. To compensate for the unequal size ofthe segments, sixth structure 300 may include counterweight 309 topreserve the dynamic balance of sixth structure 300, as describedpreviously. In this embodiment, first reflection sector 304 includes acoating to reflect a first color and second reflection sector 308includes a coating to reflect a second color (FIGS. 10 and 11). Theangular extent of first reflection sector 304 is greater than theangular extent of second reflection sector 308 by an amount sufficientto compensate for differences in a response sensitivity of first imagingsensor 14 to the first color as compared to the second color, an ocularsensitivity of a human observer to the first color as compared to thesecond color, or possibly both.

Therefore, if the desire is to improve the blue response of firstimaging sensor 14, the larger first reflection sector 304 would becoated to reflect the color blue while second reflection sector 308 iscoated to reflect either red or green, thus increasing the time overwhich first imaging sensor 14 accumulates charge for the color blue withrespect to the colors red or green. Similarly, if the desire is toimprove the human observational sensitivity of the image produced byfirst imaging sensor 14, the larger first reflection sector 304 would becoated to reflect the color green while second reflection sector 308 iscoated to reflect either red or blue, thus increasing the time overwhich first imaging sensor 14 accumulates charge for the color greenwith respect to the colors red or blue.

In FIG. 14, seventh structure 310 is a variation of first structure 110in which first transmission sector 312 and second transmission sector316 are each characterized by a corresponding angular extent and theangular extent of first transmission sector 312 is unequal to theangular extent of second transmission sector 316. To compensate for theunequal size of the segments, seventh structure 310 may includecounterweights 320 and 321 to preserve the dynamic balance of seventhstructure 310, as described previously. In this embodiment, firsttransmission sector 312 includes a coating to pass a first color andsecond transmission sector 316 includes a coating to pass a second color(FIG. 12). The angular extent of first transmission sector 312 isgreater than the angular extent of second transmission sector 316 by anamount sufficient to compensate for differences in a responsesensitivity of second imaging sensor 16 to the first color as comparedto the second color, an ocular sensitivity of a human observer to thefirst color as compared to the second color, or possibly both.

Therefore, if the desire is to improve the blue response of secondimaging sensor 16, the larger first transmission sector 312 would becoated to pass the color blue while second transmission sector 316 iscoated to pass either red or green, thus increasing the time over whichsecond imaging sensor 16 accumulates charge for the color blue withrespect to the colors red or green. Similarly, if the desire is toimprove the human observational sensitivity of the image produced bysecond imaging sensor 16, the larger first transmission sector 312 wouldbe coated to pass the color green while second transmission sector 316is coated to pass either red or blue, thus increasing the time overwhich first imaging sensor 14 accumulates charge for the color greenwith respect to the colors red or blue.

FIGS. 13 and 14 also illustrate the situation where first reflectionsector 304 or 314 and first transmission sector 302 or 316 are eachcharacterized by a corresponding angular extent and the angular extentof first reflection sector 304 or 314 is unequal to the angular extentof first transmission sector 302 or 316. Where the desire is to improvethe response of first imaging sensor 14 (FIG. 13), the larger firstreflection sector 304 includes a coating to reflect a first color andfirst transmission sector 302 includes a coating to pass a second color.The angular extent of first reflection sector 304 is greater than theangular extent of first transmission sector 302 by an amount sufficientto compensate for differences in a first response sensitivity of firstimaging sensor 14 to the first color as compared to a second responsesensitivity of second imaging sensor 16 to the second color, an ocularsensitivity of a human observer to the first color as compared to thesecond color, or possibly both.

Therefore, if the desire is to improve the blue response of firstimaging sensor 14, the larger first reflection sector 304 would becoated to reflect the color blue while first transmission sector 302 iscoated to pass either red or green, thus increasing the time over whichfirst imaging sensor 14 accumulates charge for the color blue withrespect to the time over which second imaging sensor 16 accumulatescharge for the colors red or green. Similarly, if the desire is toimprove the human observational sensitivity of the image produced byfirst imaging sensor 14, the larger first reflection sector 304 would becoated to reflect the color green while first transmission sector 302 iscoated to pass either red or blue, thus increasing the time over whichfirst imaging sensor 14 accumulates charge for the color green withrespect to the time over which second imaging sensor 16 accumulatescharge for the colors red or blue.

Similarly, where the desire is to improve the response of second imagingsensor 16 (FIG. 14), the larger first transmission sector 302 includes acoating to pass a first color and first reflection sector 304 includes acoating to reflect a second color. The angular extent of firsttransmission sector 302 is greater than the angular extent of firstreflection sector 304 by an amount sufficient to compensate fordifferences in a first response sensitivity of second imaging sensor 16to the first color as compared to a second response sensitivity of firstimaging sensor 14 to the second color, an ocular sensitivity of a humanobserver to the first color as compared to the second color, or possiblyboth.

Therefore, if the desire is to improve the blue response of secondimaging sensor 16, the larger first transmission sector 302 would becoated to pass the color blue while first reflection sector 304 iscoated to reflect either red or green, thus increasing the time overwhich second imaging sensor 16 accumulates charge for the color bluewith respect to the time over which first imaging sensor 14 accumulatescharge for the colors red or green. Similarly, if the desire is toimprove the human observational sensitivity of the image produced bysecond imaging sensor 16, the larger first transmission sector 302 wouldbe coated to pass the color green while first reflection sector 304 iscoated to reflect either red or blue, thus increasing the time overwhich second imaging sensor 16 accumulates charge for the color greenwith respect to the time over which first imaging sensor 14 accumulatescharge for the colors red or blue.

In FIG. 15, eighth structure 330 is a variation of second structure 120in which first reflection sector 332 and first transmission sector 336are each characterized by a corresponding angular extent and the angularextent of first reflection sector 332 is unequal to the angular extentof first transmission sector 336. To compensate for weight loss whenfirst transmission sector 336 is an air-filled gap, eighth structure 330may include counterweights 338 and 339 to preserve the dynamic balanceof eighth structure 330, as described previously.

In this embodiment, second imaging sensor 16 includes an array 210 ofpixel groups 220 (FIG. 8). First pixel group 220 includes a plurality ofpixels, e.g., pixels 222, 224, 226, 228, which are arranged to image avariety of colors by overlaying the pixels with color-specificmicrofilters, as described previously. The plural pixels of first pixelgroup 220 includes a first pixel 222 and the first pixel 222 is overlaidwith first color microfilter 232 (FIG. 9), thus allowing second imagingsensor 16 to image a particular color. First reflection sector 332includes a coating to reflect a first color and first color microfilter232 selects a second color. Alternatively, first color filter 18 isdisposed along reflected axis 28 between rotatable structure 100 andfirst imaging sensor 14 (FIG. 1) to image the first color, obviating theneed for the reflection coating. The angular extent of first reflectionsector 332 is greater than the angular extent of first transmissionsector 336 by an amount sufficient to compensate for differences in afirst response sensitivity of first imaging sensor 14 to the first coloras compared to a second response sensitivity of second imaging sensor 16to the second color, an ocular sensitivity of a human observer to thefirst color as compared to the second color, or possibly both.

Therefore, if the desire is to improve the blue response of firstimaging sensor 14, the larger first reflection sector 332 would becoated to reflect the color blue while microfiltered pixel array 210overlaying second imaging sensor 16 selects either red or green, thusincreasing the time over which first imaging sensor 14 accumulatescharge for the color blue with respect to the time over which secondimaging sensor 16 accumulates charge for the colors red or green.Similarly, if the desire is to improve the sensitivity to be comparableto human observational sensitivity of the image produced by firstimaging sensor 14, the larger first reflection sector 332 would becoated to reflect the color green while microfiltered pixel array 210overlaying second imaging sensor 16 selects either red or blue, thusincreasing the time over which first imaging sensor 14 accumulatescharge for the color green with respect to the time over which secondimaging sensor 16 accumulates charge for the colors red or blue. Inother embodiments, microfiltered pixel array 210 overlying secondimaging sensor 16 may select two colors, e.g., red and green or red andblue.

In FIG. 16, ninth structure 340 is a variation of second structure 120in which first reflection sector 342 and first transmission sector 346are each characterized by a corresponding angular extent and the angularextent of the angular extent of first reflection sector 342 is unequalto the angular extent of first transmission sector 346. To compensatefor weight loss when first transmission sector 340 is an air-filled gap,ninth structure 340 may include counterweights 348 and 349 to preservethe dynamic balance of ninth structure 340, as described previously.

In this embodiment, first imaging sensor 14 includes an array 210 ofpixel groups 220 (FIG. 8). First pixel group 220 includes a plurality ofpixels, e.g., pixels 222, 224, 226, 228, which are arranged to image avariety of colors by overlaying the pixels with color-specificmicrofilters, as described previously. The plural pixels of first pixelgroup 220 includes a first pixel 222 and the first pixel 222 is overlaidwith first color microfilter 232 (FIG. 9), thus allowing first imagingsensor 14 to image a particular color. First transmission sector 346includes a coating to pass a first color and first color microfilter 232selects a second color. Alternatively, second color filter 20 isdisposed along direct axis 26 between rotatable structure 100 and secondimaging sensor 16 (FIG. 1) to image the first color, obviating the needfor the transmission coating. The angular extent of first transmissionsector 346 is greater than the angular extent of first reflection sector342 by an amount sufficient to compensate for differences in a firstresponse sensitivity of second imaging sensor 16 to the first color ascompared to a second response sensitivity of first imaging sensor 14 tothe second color, an ocular sensitivity of a human observer to the firstcolor as compared to the second color, or possibly both.

Therefore, if the desire is to improve the blue response of secondimaging sensor 16, the larger first transmission sector 346 would becoated to pass the color blue while microfiltered pixel array 210overlaying first imaging sensor 14 selects either red or green, thusincreasing the time over which second imaging sensor 16 accumulatescharge for the color blue with respect to the time over which firstimaging sensor 14 accumulates charge for the colors red or green.Similarly, if the desire is to improve the human observationalsensitivity of the image produced by second imaging sensor 16, thelarger first transmission sector 346 would be coated to pass the colorgreen while microfiltered pixel array 210 overlaying first imagingsensor 14 selects either red or blue, thus increasing the time overwhich second imaging sensor 16 accumulates charge for the color greenwith respect to the time over which first imaging sensor 14 accumulatescharge for the colors red or blue. In other embodiments, microfilteredpixel array 210 overlying first imaging sensor 14 may select two colors,e.g., red and green or red and blue.

3-Chip Camera

In FIG. 17, 3-chip camera 400 includes lens 402, first imaging sensor404, second imaging sensor 406, third imaging sensor 408, firstrotatable structure 430, and second rotatable structure 440. Firstimaging sensor 402 is disposed to image light that propagates alongfirst reflected axis 425, second imaging sensor 406 is disposed to imagelight that propagates along second reflected axis 426, and third imagingsensor 408 is disposed to image light that propagates along direct axis424. First rotatable structure 430 is disposed to define a firstrotation plane that is oblique to first reflected axis 425 and directaxis 424. Second rotatable structure 440 is disposed to define a secondrotation plane that is oblique to second reflected axis 426 and directaxis 424.

In operation, first motor 418 rotates first axle 416 that in turnrotates first rotatable structure 430, and second motor 422 rotatessecond axle 420 that in turn rotates second rotatable structure 440.Lens 402 focuses an image conjugate onto third imaging sensor 408 alongdirect axis 424 such that third imaging sensor 408 converts the imagelight into electrical signals. Lens 402 also focuses the image conjugateonto first imaging sensor 404 along first reflected axis 425. The imagelight through lens 402 along direct axis 424 is reflected from areflection sector of first rotatable structure 430 to propagate alongfirst reflected axis 425. First imaging sensor 404 converts the imagelight into electrical signals. Lens 402 further focuses the imageconjugate onto second imaging sensor 406 along second reflected axis426. The image light through lens 402 along direct axis 424 is reflectedfrom a reflection sector of second rotatable structure 440 to propagatealong second reflected axis 426. Second imaging sensor 406 converts theimage light into electrical signals. First and second rotatablestructures 430 and 440 are formed having an inner radius such that theimage light focused by lens 402 does not impinge on either first motor418 or second motor 422 but only on the surface of rotatable structures430 and 440. Other formations of first and second rotatable structures430 and 440 are also possible that satisfy the need to avoid first andsecond motors 418 and 422.

In some variants of the invention, camera 400 also includes first colorfilter 410 disposed along first reflected axis 425 between firstrotatable structure 430 and first imaging sensor 404. In other variantsof the invention, camera 400 further includes second color filter 412disposed along second reflected axis 426 between second rotatablestructure 440 and second imaging sensor 406. In further variants of theinventions, camera 400 additionally includes third color filter 414disposed along direct axis 424 between first and second rotatablestructures 430 and 440 and third imaging sensor 408.

First and second rotatable structures 430 and 440 are represented asrotatable structure 450 (FIG. 18A) that includes first reflection sector452 and “air-filled” first transmission sector 454 disposed adjacent tofirst reflection sector 452. First transmission sector 454 is a gap(i.e., air-filled), as indicated by reference numeral 454. By makingfirst transmission sector 454 a gap, first and second rotatablestructures 430 and 440 can be positioned and phased such that thereflection sectors of rotatable structures 430 and 440 do not collide asrotatable structures 430 and 440 are being rotated. Rotatable structure450 also includes counterweight 456, which serves to offset the massdistribution differential caused by first transmission sector 454 beingan air-filled gap, thus preserving dynamic balance in rotatablestructure 450. The dynamic balancing function of rotatable structure 450may be achieved by other means, for example, relocating the placement ofaxle attachment point 416 or 420 to create a dynamically balancedrotatable structure.

Preferably, first reflection sector 452 of rotatable structures 430 and440 covers one-third of a circle and is coated such that rotatablestructures 430 and 440 each reflect a respective color (e.g., onerotatable structure reflects blue and the other reflects red).Alternatively, color filters 410, 412, and 414 may be used to select theappropriate color to impinge on imaging sensors 404, 406, and 408. Amotor control unit controls the motor speed and phase so that rotatablestructures 430 and 440 do not collide, and in fact, so that there existsa time when neither rotatable structure is positioned at the exit pupilof lens 402 so as to interrupt the direct light path through lens 402and onto third imaging sensor 408.

FIG. 18B shows a front view (as seen from lens 402) of the preferredoverlap positioning of superimposed rotatable structures 430 and 440during operation of the 3-chip camera 400. A motor control unit controlsthe motor speed and phase of motors 418 and 422 so that during a firstthird of a revolution, imaging light of a first color is reflected fromfirst reflection sector 452 onto first imaging sensor 404. During thenext one-sixth of the revolution, first and second transmission sector454 overlap and allow imaging light of a second color to be reflectedonto third imaging sensor 408. During the next one-third of therevolution, imaging light of a third color is reflected from secondreflection sector 452′ onto second imaging sensor 406. During the lastone-sixth of the revolution, imaging light of the second color passesagain through first and second transmission sector 454 onto thirdimaging sensor 408. An advantage of 3-chip camera 400 is that theimaging light passes through nothing but air, or third color filter 414,while passing from lens 402 to third imaging sensor 408. High qualitycolor images are obtained. When the imaging light must pass through somesubstrate material, e.g., a glass transmission sector some attenuationand/or distortion might be present. Although the scenario describedabove presumes that the overlapping transmission sector regions are eachone-sixth of a circle, other variations are possible and will not effectthe operation of the 3-chip camera 400.

In an alternative embodiment, first and second rotatable structures 430and 440 include an integral counterweight formed with the reflectionsector (FIG. 18C). Rotatable structure 460 is machined to includereflection sector 462, “air-filled” gap transmission sector 464, andintegral counterbalance 466. In FIG. 18D integral rotatable structure460 is coupled through axle 416 to motor 418. In one variation,reflection sector 462 and integral counterbalance 466 are formed from ametal slug which is either milled or broached to the shape of structure460 and so as to include axle hole 416. A portion of the integralstructure is then milled or broached to thin the portion and formreflection sector 462 into a thinner thickness (see FIG. 18D). The metalsector that forms reflection sector 462 is then polished and plated to aflat reflection surface. The thickness of reflection sector 462 and thethickness of integral counterbalance 466 are designed to maintaindynamic balance in rotatable structure 460 about axle 416.

In another variation, reflection sector 462 may be formed of thinnerstock (of a material such as glass, plastic, or metal) and thicker (Dshaped) portions are bonded to the thinner stock at bonding surfaces 467to form counterbalance portion 466. The thickness of reflection sector462 and the thickness of bonded counterbalance 466 are designed tomaintain dynamic balance in rotatable structure 460 about axle 416.

FIG. 27 illustrates a timing diagram for the operation of the 3-chipcamera 400. Timing for the operation of first imaging sensor 404 isdenoted generally by reference numeral 1700, timing for the operation ofsecond imaging sensor 406 is denoted generally by reference numeral1730, and timing for the operation of third imaging sensor 408 isdenoted generally by reference numeral 1760. The operation of firstrotatable structure 110 is separated into eight regions (denoted byRoman numerals I-VIII) that correspond to the sectors of first rotatablestructure 110. The vertical axes in timing diagrams 1700, 1730, and 1760represents the number of pixels illuminated in first, second, and thirdimaging sensors 404, 406, and 408, respectively. The horizontal axesrepresents the time, or phase, of the rotation of first and secondrotatable structures 430 and 440.

Region I in timing diagram 1700 shows the charge integration in firstimaging sensor 404 while the image light reflects from a central area offirst reflection sector 452 such that every pixel on first imagingsensor 404 is illuminated. Charge is integrated in first imaging sensor404 while the image light reflects from first reflection sector 452 ontofirst imaging sensor 404. As the rotatable structures 430 and 440rotate, first reflection sector 452 moves out of the objective path oflens 402 while “air-filled” gap transmission sector 454 moves into theobjective path of lens 402. Fewer pixels of first imaging sensor 404 areilluminated, as shown by region II in timing diagram 1700, as firstreflection sector 452 moves out of the objective path. In oneembodiment, charge integrates in first imaging sensor 404 only whilefirst imaging sensor 404 is fully illuminated (bracket 1). In analternative embodiment, charge integration in first imaging sensor 404begins as first reflection sector 452 moves into the objective path oflens 402 and continues as first reflection sector 452 moves out of theobjective path of lens 402 and fewer pixels in first imaging sensor 404are illuminated (bracket 2).

Once “air-filled” gap transmission sector 454 has moved completely intothe objective path of lens 402, the image light no longer reflects ontofirst imaging sensor 404, as shown by region III in timing diagram 1700.Charge is transferred (Xfer 1) from first imaging sensor 404 while“air-filled” gap transmission sector 454 passes the image to the thirdimaging sensor or second reflection sector 452′ of the second rotatablestructure 440 reflects light to the second imaging sensor so as toprevent the image light from impinging on first imaging sensor 404.

Timing diagram 1760 shows the charge integration in third imaging sensor408 while the image light passes through an increasing portion of “airfilled” gap transmission sector 454 (region II) until the image lightpasses through a central area of “air-filled” gap transmission sector454 such that approximately half the total number of pixels on secondimaging sensor 406 are illuminated (region III). Charge is integrated inthird imaging sensor 408 while the image light passes through“air-filled” gap transmission sector 454 onto third imaging sensor 408.As the rotatable structures 430 and 440 rotate, “air-filled” gaptransmission sector 454 moves out of the objective path of lens 402while second reflection sector 452′ moves into the objective path oflens 402. Fewer pixels of third imaging sensor 408 are illuminated, asshown by region IV in timing diagram 1760, as second reflection sector452′ moves into the objective path. In one embodiment, charge integratesin third imaging sensor 408 only while third imaging sensor 408 ismaximally illuminated (bracket 1). In an alternative embodiment, chargeintegration in third imaging sensor 408 begins as “air-filled” gaptransmission sector 454 moves into the objective path of lens 402 andcontinues as “air-filled” gap transmission sector 454 moves out of theobjective path of lens 402 (region IV) and fewer pixels in third imagingsensor 408 are illuminated (bracket 2).

Once second reflection sector 452′ has moved completely into theobjective path of lens 402, the image light no longer reflects ontothird imaging sensor 408 (region V). Charge is transferred (Xfer 1) fromthird imaging sensor 408 while second reflection sector 452′ preventsthe image light from impinging on third imaging sensor 408.

Timing diagram 1730 shows the charge integration in second imagingsensor 406 while the image light reflects from an increasing portion ofsecond reflection sector 452′ (region IV) until the image light reflectsfrom a central area of second reflection sector 452′ such thatapproximately half the total number of pixels on second imaging sensor406 are illuminated (region III). Charge is integrated in second imagingsensor 406 while the image light reflects from second reflection sector452′ onto second imaging sensor 406. As the rotatable structures 430 and440 rotate, second reflection sector 452′ moves out of the objectivepath of lens 402 while “air-filled” gap transmission sector 454′ movesinto the objective path of lens 402. Fewer pixels of second imagingsensor 406 are illuminated, as shown by region VI in timing diagram1730. In one embodiment, charge integrates in second imaging sensor 406only while second imaging sensor 406 is fully illuminated (bracket 1).In an alternative embodiment, charge integration in second imagingsensor 406 begins as second reflection sector 452′ moves into theobjective path of lens 402 and continues as second reflection sector452′ moves out of the objective path of lens 402 and fewer pixels insecond imaging sensor 406 are illuminated (bracket 2).

The cycle of charge integration in third imaging sensor 408 is repeatedas “air-filled” gap transmission sector 454′ moves into and out of theobjective path of lens 402 and the image light passes through“air-filled” gap transmission sector 454′ onto third imaging sensor 408(regions VI-VIII). Charge is again transferred from third imaging sensor408 once first reflection sector 452 is completely in the objective pathof lens 402, thus preventing the image light from impinging on thirdimaging sensor 408 (region I). The entire cycle begins anew as firstreflection sector 452 moves back into the objective path of lens 402(region I in timing diagram 1700).

If first and second reflection sectors 452 and 452′ are not completelyreflective and if “air-filled” gap transmission sectors 454 and 454′ arenot completely transmissive, imaging sensors 404, 406, and 408 mayinclude electronic shutter control such that neither sensor is capableof integrating charge during the charge transfer phase of theiroperation in order to avoid smear artifacts.

Furthermore, due to the wedge shape of reflection sectors 452 and 452′and “air-filled” gap transmission sectors 454 and 454′, the pixels ofimaging sensors 404, 406, and 408 disposed along the outer radius of therotatable structures 430 and 440 will be illuminated for a longer periodof time than the pixels disposed along the inner radius of the rotatablestructures 430 and 440. The resulting image may be adjusted inpost-processing to allow for the difference in the amount of chargeintegrated for different parts of the image. The pixel values can beweighted allow for normalization of the resulting image.

In FIG. 28 (a variant of the embodiment of FIG. 1), camera 2100 includesa lens generally disposed at plane 2101 but focusable to a location at2104, first imaging sensor 2114, second imaging sensor 2116, androtatable structure 2200. First imaging sensor 2114 is disposed toreceive light that propagates along reflected axis 2128 and secondimaging sensor 2116 is disposed to receive light that propagates alongdirect axis 2126. Rotatable structure 2200 is disposed to define arotation plane that is oblique to both reflected axis 2128 and directaxis 2126. In operation, motor 2124 rotates axle 2122 that in turnrotates rotatable structure 2200. The lens at plane 2102 focuses animage conjugate onto second imaging sensor 2116 along direct axis 2126such that second imaging sensor 2116 converts the image light intoelectrical signals. This focal length, denoted 2101A, is about 52millimeters in this example. The lens at plane 2102 also focuses theimage conjugate onto first imaging sensor 2114 along reflected axis2128. The image light through the lens along direct axis 2126 isreflected from a reflection sector of rotatable structure 2200 topropagate along reflected axis 2128. First imaging sensor 2114 convertsthe image light into electrical signals. Rotatable structure 2200 isformed as a ring having an inner radius such that the image lightfocused by the lens does not impinge on motor 2124 but only on thesurface of rotatable structure 2200.

In camera 2100 of FIG. 28, light may be focused by the lens in theregion between angles 2105 and 2106. An image center point is defined atthe intersection of reflected axis 2128 (with centerline label) anddirect axis 2126 (with centerline label), or at distance 2101B, about 39millimeters behind plane 2102 in this example. Light is focused by thelens through the area between angle 2105 and 2106. In this example, theangle between angle 2105 and direct axis 2126 is 45 degrees, and theangle between direct axis 2126 and angle 2106 is also 45 degrees.However, in this example, the plane of rotation of rotatable structure2200 and angle 2106 is 2.5 degrees. This tends to avoid certainreflection issues in the camera. Sensor 2114 is disposed perpendicularto reflection axis 2128, and therefore, sensor 2114 is canted by angle2109 (5 degrees in this example) with respect to direct axis 2126. Theimage conjugate is focused through aperture 2110 that is comparable tothe vertical aperture used in 35 millimeter film cinematography.

Second sensor 2116 is mounted in package 2117 and covered with atransparent window. Distance 2119 between the transparent window outersurface and the sensor top surface is about 1.8 millimeters in thisexample. Similarly, first sensor 2114 is mounted in package 2115 andcovered with a transparent window.

Having described preferred embodiments of a novel chopped color camerawith solid state imaging sensors (which are intended to be illustrativeand not limiting), it is noted that modifications and variations can bemade by persons skilled in the art in light of the above teachings. Itis therefore to be understood that changes may be made in the particularembodiments of the invention disclosed which are within the scope andspirit of the invention as defined by the appended claims.

Having thus described the invention with the details and particularityrequired by the patent laws, what is claimed and desired protected byLetters Patent is set forth in the appended claims.

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 8. A method comprising (1) operating a firstsensor of a camera to integrate a first charge over a first timeinterval defined as beginning when image light first impinges on thefirst sensor and continuing as long as the image light continuouslyimpinges on the first sensor, (2) operating a second sensor of thecamera to integrate a second charge over a second time interval and (3)scanning the first and second sensors to readout the respective firstand second charges during a third time interval, wherein: the operatingthe first sensor includes integrating the first charge in the firstsensor while a first image light reflects from a first reflection sectorof a rotatable structure onto the first sensor; the operating the secondsensor includes integrating the second charge in the second sensor whilea second image light passes through a first transmission sector of therotatable structure onto the second sensor; the scanning includestransferring the integrated first and second charges from the respectivefirst and second sensors while a first opaque sector of the rotatablestructure prevents the first and second image light from impinging on atleast one of the first and second sensors; the first time intervaloverlaps the second time interval; the third time interval includes nooverlapping time with the first time interval; and the third timeinterval includes no overlapping time with the second time interval. 9.A method comprising: operating a first sensor of a camera over a firsttime interval to integrate a first charge in the first sensor while afirst image light reflects from a first reflection sector of a rotatablestructure onto the first sensor; operating a second sensor of the cameraover a second time interval to integrate a second charge in the secondsensor while a second image light passes through a first transmissionsector of the rotatable structure onto the second sensor; and scanningthe first and second sensors during a third time interval to transferthe respective integrated first and integrated second charges from therespective first and second sensors while a first opaque sector of therotatable structure prevents the first and second image light fromimpinging on at least one of the first and second sensors, wherein thefirst time interval overlaps a fractional part of the second timeinterval, and wherein the third time interval includes no overlappingtime with the first time interval and the third time interval includesno overlapping time with the second time interval.
 10. A methodcomprising: operating a first sensor of a camera over a first timeinterval to integrate a first charge in the first sensor while a firstimage light reflects from a first reflection sector of a rotatablestructure onto the first sensor; operating a second sensor of the cameraover a second time interval to integrate a second charge in the secondsensor while a second image light passes through a first transmissionsector of the rotatable structure onto the second sensor; and scanningthe first and second sensors during a third time interval to transferthe respective integrated first and integrated second charges from therespective first and second sensors while a first opaque sector of therotatable structure prevents the first and second image light fromimpinging on at least one of the first and second sensors, wherein thesecond time interval overlaps one and only one of a beginning and an endof the first time interval, and wherein the third time interval includesno overlapping time with the first time interval and the third timeinterval includes no lapping time with the second time interval.